[time-nuts] HP 3586B Power Supply Failures

Perry Sandeen sandeenpa at yahoo.com
Thu Mar 22 04:55:39 UTC 2012


List,

The other day I had my second HP 3586B power supply board smoked.  It burned both the PC board traces and the connector on the motherboard so badly it will have to be replaced.  Also an inch or so of one trace on the mother board but it looks like it will be repairable.  Fortunately I have a donor board for the connector but it will probably be an all-day project to do the repair properly.

An observation.  There AFAIK a fold-back current limiting circuit but it didn’t help and the correct value of primary fuse did not blow.  This made me an extremely unhappy camper.  I’m also going to try and figure out how to add additional fuses.  

So I went through the entire instrument and came up with a list of all the Sprague TVA electrolytics that I am going to replace as they are dated coded 1983.

So two questions.  One, can I safely double the capacitance of the filter capacitors?  (I plan on using the 105C 10K hour high reliability Nichicon or Panasonic units.)  

Secondly, the tantalum filter caps seem OK but can they be replaced with the same high quality aluminum electrolytics perhaps of a higher value of capacitance?

Additionally, I plan on doing the same to all my vintage HP test equipment.  A smoked 5370B would really, really, really, ruin my week.

Opinions and solutions sought.

Regards,

Perrier 





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